RF-MEMS

Messergebnisse von Isolation und Einfügedämpfung

Electrostatic actuated Ohmic switches in series SPST configuration for DC up to 4 GHz signal frequency (<0.5 dB insertion los, 35 dB isolation) and in shunt switch SPST configuration for a frequency range from RF up to 75 GHz (<1.2 dB insertion los, 20 dB isolation) were developed. A novel high aspect ratio MEMS fabrication sequence in combination with wafer level packaging is applied for fabrication of the samples and allows for a relatively large actuation electrode area, and for high actuation force resulting in fast on-response time of 10 µs and off-response time of 6 µs at less than 5 Volt actuation voltage.

Large actuation electrode area and a particular design feature for electrode over travel and dynamic contact separation lead to high contact force in the closed state and to high force for contact separation to overcome sticking. The switch contacts are consisting of noble metal, and are made in one of the latest process steps which prevents contamination of the contact surfaces by fabrication sequence residuals. A life time of 10e9 switch cycles has been achieved. The switch devices are hermetically sealed by wafer level packaging. A defined vacuum pressure leads to optimized response time and no contact ringing. It was shown by a long term life time test that the electrostatic drive system is free of charging.